Adjusting device for water turbine guide apparatus



Nov. 7, 1961 A. 5055 3 ,007,675

ADJUSTING DEVICE FOR WATER TURBINE GUIDE APPARATUS Filed Oct. 12, 1959 2 Sheets-Sheet 1 INVENTOR. Arnold 5115s BY djgfa .APco'rnegs Nov. 7, 196-1 5055 3,007,675

ADJUSTING DEVICE FOR WATER TURBINE GUIDE APPARATUS Filed Oct. 12, 1959 2 Sheets-Sheet 2 INVENTOR.

Arnold. Silss Aitorne gs United States Patent Office 3,007,675 Patented Nov. 7., 1961 3,007,675 ADJUSTING-DEVICE FOR WATER TURBINE GUIDE APPARATUS Arnold Siiss, Zurich, Switzerland, assignor to Escher Wyss Aktiengesellschaft, Zurich, Switzerland, :1 corporation of Switzerland Filed Oct. 12, 1959, Ser. No. 845,762 Claims priority, application Switzerland Oct. 16, 1958 Claims. (Cl. 253-31) As a rule, no special shut-off members are provided in front of large low-pressure water turbines, that is to say, more particularly in front of Kaplan turbines, since such members are relatively expensive, due to their size. From the beginning of the construction of large Kaplan turbines, therefore, their adjustable guide apparatus has been provided with a lock which, when the servomotor is without pressure, holds the guide apparatus fast in its closed position against the vane restoring forces developed by the water. For simplification of the control, however, it is desirable to dispense with this lock.

This invention now relates to the adjusting device for the servomotor-operated guide apparatus of a water turbine and the aforesaid simplification is made possible ac cording to the invention by the fact that the adjusting linkage between the servomotor and the guide vanes has a toggle lever mechanism which, in the closed position of the guide apparatus, attains at least the dead-centre position, so that the guide apparatus remains in its closed position when the servomotor is without pressure.

Constructional examples of the subject of the invention are illustrated in simplified representation in the drawing, wherein:

FIGURE 1 shows an adjusting device with a central regulating ring operating the guide apparatus.

FIGURE 2 shows another constructional form of an adjusting device with regulating ring, and

FIGURE 3 shows an adjusting device, in which each vane of the guide apparatus is adjusted by a separate servomotor.

FIGURE 1 shows two adjustable vanes 1 of the guide apparatus of a water turbine, which is intended to feed a whirling body of water to the turbine runner (not shown). In the closed position, each guide vane bears against the adjacent guide vane in the vicinity of its trailing edge 2. The guide apparatus is operated by a pressure-fluid actuated servomotor with cylinder 3 and piston 4. The pressure fluid supply lines are indicated at 5 and 6. The movement of the piston 4 is transmitted by a piston rod 7 and a connecting rod 8 to a regulating ring 9 mounted coaxially with the turbine. In the region of each guide vane, this regulating ring is provided with a projection 10, to which is pivoted one end of a link 11. The other end of the link is pivoted to a lever 12 for operating the guide vane. The vane has a pivot 13 to which said lever 12 is rigidly connected. 14 and 15 are hinge points between regulating ring projection 10 and link 11, and between link 11 and lever 12, respectively. The parts 7, 8, 9, 10, 11, 12, 13 form the adjusting linkage between the servomotor 3, 4 and the guide vanes 1.

In the open position of the guide apparatus, the piston 4 of the servomotor is in a position 4', the link 11 in a position 11, the lever 12 in a position 12', and the pivots 14, are in positions 14 and 15', respectively. To bring the guide vanes 1 to their closure position, pressure medium is admitted through the supply line 6 to the cylinder 3 of the servomotor. The piston 4 then moves from its end position 4 to the left, until due to the rotation of the ring 9 on its axis, the hinge points 14 has passed from its position 14' to a position 14", in which the hinge point 15 assumes the position shown and the vane 1 is in the closed position. Due to the vane 1 bearing on the adjacent vane, the vane can no longer rotate beyond this position.

,In the position 14 of the hinge point 14, the link 11 is almost in its dead centre position. The servomotor, however, is moved still farther to the left. The dead centre position of the link 11 is attained when the hinge point 14 has reached the position shown at 14". The hinge point 15, however, then reaches a position 15 displaced outwardly by a small amount, which since the vane 1 can no longer rotate is possible only with elastic deformation of the lever 12 or the blade pivot 13.

The parts 10, 11 of the adjusting linkage between the regulating ring 9 operating the guide apparatus and the guide vane 1 form a toggle lever mechanism. Each of the other guide vanes of the guide apparatus has a corresponding toggle lever mechanism associated with it. In the dead centre position 14", 15" of the hinges 14, 15, the link 11 is in a radial direction with reference to the axis of the regulating ring. Water pressure, acting on the vanes 1, develops vane restoring forces which tend to move each vane in a counterclockwise direction about its pivot 13 to an open position. However, since these forces are transmitted to ring 9 through links 11, and since these links are now in radial positions with respect to the ring, the forces do not exert any torque on the ring. The guide apparatus thus remains in its closed position even when the servomotor is without pressure.

In the adjusting device shown, however, the end position of the piston 4 of the servomotor on closure of the guide apparatus is so selected that the hinge point 14 lies beyond its dead centre position 14". Vane restoring forces transmitted by the link 11 then produce a torque acting on the regulating ring 9 in the closing direction, so that the piston 4 is held fast in its end position and hence the guide apparatus in its closed position. If the resiliency in any event already present in the adjusting members is not sufficient to permit the dead centre position of the toggle lever mechanism to he reached, a special resilient member may also be provided in the toggle lever mechanism.

In the device according to FIGURE 2 the vanes of the guide apparatus of the water turbine, of which only one is shown at 16, are operated by a servomotor with cylinder 17 and piston 18 via a regulating ring 19 mounted coaxially with the guide apparatus. The adjusting linkage consists of a piston rod 20 rigidly connected to the piston 18, a link 21, a radius link 22, a link 23, a further link 24 and a lever 25, 26, 27, 28, 29, and 30 denote hinge points and 31 is a fixed pivot, to which the radius link 23 is pivoted. The link 21 is connected at the hinge point 26 to the piston rod 20 and at the hinge point 27 to the outer end of the radius link 22 and one end of the link 23. By its other end, the link 23 is connected at the hinge point 28 to a projection 32 of the regulating ring 19. The guide vane 16 has a pivot 33 on which is mounted the lever 25. The link 24 connects at the hinge points 29 and 30 a projection 34 of the regulating ring 19 to the outer end of lever 25.

The guide vane 16 is shown in its closed position. In the open position of the guide apparatus, the hinge points 26, 27, 28, 2%, 30 are in the positions denoted by 26', 27', 28', 29, 30', and the piston 18 is in its rear end position shown at 18'. If now pressure medium is admitted behind the piston 18', a closing movement of the guide apparatus is initiated and the radial link 22 and the link 23 approach the extended position, that is to say, the position in which the hinge point 27 lies on the straight line connecting the hinge point 28 and the fixed pivot 31. Shortly before, however, the closure position of the vane 16 is reached. Before, however, the piston 18 has reached the front end position shown, the

hinge point 27 will be forced beyond the straight line connecting the points 28 and 31, so that restoring forces originating from the guide apparatus will no longer be able! to move the piston 18 from its end position and open the guide vanes, even when the servomotor 17, 18 is without pressure. The parts 22, 23 of the adjusting linkage between the servomotor 17, 18 and the regulating ring 19 operating the guide vanes here form a toggle lever mechanism, the extended position of these parts representing its dead centre position.

According to FIGURE 3, it is assumed that each guide vane has a separate servomotor associated with it. Only a single guide vane 35 with vane pivot 36 is shown. It is operated by a servomotor with cylinder 37 and piston 38. The adjusting linkage is formed by a piston rod 39, rigidly connected to the piston 38, a link 40, a radius link 42 turning on a fixed pivot 41, a link 43 and a lever 44 mounted on the pivot 36 of the vane 35. The link 42 is connected at a hinge point 45 to the connecting rod 39 and at a hinge point 46 to the radius link 42, and one end of the link 43. The other end of the link 43 is connected at a hinge point 47 to the lever 44.

In the open position of the guide vane, the hinges 45, 46, 47 assume the positions denoted by 45, 46, 47. The radius link 42 and the link 43 form a toggle lever mechanism. Shortly before reaching the closure position shown of the servomotor piston 38, the part 42, 43 reach their dead centre position, that is to say, hinge point 46 reaches the straight line connecting the hinge 47 and the fixed pivot 41. Before the piston 38 reaches the end position, the hinge point 46 passes the said connecting line. Restoring forces originating from the vane and counteracting the closure movement are in this case also unable to cause a displacement of the piston 38 from its end position, even when the servomotor 37, 38 is without pressure, so that the guide vane remains closed.

What is claimed is:

1. In combination, a water turbine having a guide apparatus including adjustable vanes, each vane being movable between closed and open positions and being urged toward the latter position by vane restoring forces developed by the water pressure acting on it; at least one fluid pressure actuated servomotor; and an adjusting linkage operatively connecting the servomotor with the vanes to move them between the closed and open positions, the adjusting linkage including at least one toggle lever mechanism arranged so that it reaches at least its dead centre position as the vanes reach closed position, whereby the toggle lever mechanism prevents the vane restoring forces from moving the vanes.

2. The combination defined in claim 1 in which the adjusting linkage includes a resilient member arranged to be deformed when the toggle lever mechanism is in the region of its dead centre position.

3. The combination defined in claim 1 in which the adjusting linkage includes a regulating ring that is operatively connected with the vanes; and in which the toggle lever mechanism is interposed between the servomotor and the regulating ring.

4. The combination defined in claim 1 in which the adjusting linkage includes a regulating ring that is 0peratively connected with the servomotor; and in which there are a plurality of toggle lever mechanisms, one of said mechanisms forming an operative connection between the regulating ring and each vane.

5. The combination defined in claim 1 in which there are a plurality of servomotors, one for each vane; and in which there are a plurality of toggle lever mechanisms, one interposed between each servomotor and its associated vane.

References Cited in the file of this patent UNITED STATES PATENTS 1,986,915 Biggs Jan. 8, 1935 2,344,594 Bryant Mar. 21, 1944 2,365,927 Allen Dec. 26, 1944 2,436,372 Avery Feb. 24, 1948 2,532,850 May Dec. 5, 1950 2,587,746 May Mar. 4, 1952 FOREIGN PATENTS 163,093 Switzerland Sept. 16, 1933 712,890 Germany Oct. 27, 1941 

